The Colfax chronicle. [volume] (Colfax, Grant Parish, La.) 1877-1981, 1887-06-04
COLLIERY EXPLOSIONS.
Efforts Which Have Been Made
to Prevent Them.
The "Dsvy" Lamp and Fire Damp-Coal
Dust MISREPRESENTATION to Give
Place to Safer Methods Of
Explosions.

gas, although in some the amount is SO
very small that the air within them
could never become explosive under or.
binary conditions of working. There
is no doubt that gas frequently escapes
detection owing to the imperfection OF
the means employed for its recognition.
If present in certain proportions the
marsh gas is revealed by the elonga-
ton of the flame of the safety-lamp, OF
by the appearance of what is
known as leap" upon the fame.
An experienced eye can determine pref
ty accurately the relative amount OF
the fire-damp from the size and character
Of the cap upon properly trimmed
flame; but the test altogether fails when
the proportion of gas falls below two
per cent. This amount, small as it may
seem, may, under certain circum-
stances, prove highly dangerous. The
mine-manager and the "firemen'' re-
quire to use some more delicate method
of detecting small quantities of fire.
damp than that usually employed. For
tunately such methods are not unknown.
Mi. Liveing has devised very ingeni-
Gus indicator, by which the existence
of marsh gas can be detected and its
amount estimated even when the guam
tity is as low as quarter per cent.
Two precisely similar pieces of thin
platinum wire are simultaneously
heated to bright redness by the action
of a small magneto-electric machine
worked by hand. One of the wires is
contained in small tube filled with pure
air; the other can be surrounded at will,
and in a minute or two, with air
from any part of the mine. If fire.
damp is present it burns round the hot
wire, which is thereby increased in
temperature and emits more brilliant
light. BY comparing the intensities of
the light emitted by the two wires by
the aid of very simple photometric
arrangement the percentage amount Of
fire-damp present may be at once de-
termined. The apparatus is portable
and easily worked. and is well adapted
for use under ground.
Seventy years have elapsed since Sir
Humphrey Davy invented the safety
lamp which is associated with his name.
1t is almost impossible to overestimate
the influence of that invention in the
development Of coal-mining-in the de-
velopment, indeed, of our national
prosperity. It has unquestionably
saved thousands of lives, and has en-
abled millions of tons of coal to be
raised which, without it, could not pos
sibly have been won.
1t is related that when Mr.. Buddle,
whose name is we'll known in the
history Of coal-mining for the
improvements he introduced into
the system of ventilating collieries,
took down one of the first Davy lamps
into a fiery pit and beheld the fire-damp
''cap" playing round the light and APP
parently imprisoned within the wire
gauze cylinder, he exclaimed exult-
ingly: "At last we have subdued this
monster!"
Not year passes, however, without
the monster showing us that he is
still very far from subsection; and,
strange to say, the Davy lamp itself
and the very system of ventilation
which we owe to Mr.. Buddle, as de-
veloped in these later times. have con-
spired to aid the monster III his work
of havoc and disaster.
dow this has come about NAV be
told in very few words. When the
lamp was first introduced the ventilat-
ing currents in mines seldom exceeded a
velocity of three hundred feet per
minute in the Anyways, and they were
usually very feeble in the working
places. Nowadays the enormous fans
and other mechanical ventilators which
are employed cause the air to travel at
velocities approaching two thousand
feet per minute in the anyways, and cur
rents of more than four hundred feet per
minute are not unfrequently met with
Mt the working places. Under these
conditions the Davy lamp and, in a
lesser degree, two other well-known
forms of safety lamp-the Clanny and
the Stephenson lamps-become abso-
lutely unsafe in an explosive atmos-
phere. Indeed, the ordinary Davy
lamp viii ignite gas outside it if ex-
posed to an explosive current travelling
At less than four hundred feet per min
ute
The Royal Commissioners, asfar back
- 1880. directed the attention of the
Home Secretary to the fact THAT the